Abrasive cutting



Fell 21, 1956 H. v. ALLlsoN ABRASIVE CUTTING WHEELS Filed March 26, 1955 INVENTOR. v HUGH V ALLIEEIN AT TDRNEY United States Patent O ABRASIVE Ctrr'riNG WHEELS Hugh V.-Allison,- Fairiield, Conn., assigner toAmerican Chain and Cable Company,'.lnc., Bridgeport, Conn.,a corporation of New-York- Application Marchl, 1953SerilNo. 344,816 S'Claims.. (G551-297) This invention relates to an improvement in abrasive cuttingwheels. of the type employed for cuttingy alloy steel and. other tough metals. Cuttingwheels are characterized by their relatively small. thickness and relatively large diameter, andare to be distinguished from grinding or other types of abrasive wheels in that their use is limited to.such operations as cutting, cutting-off, grooving, slotting, coping, jointing, etc., and itis the purpose of such wheels in general, and of the present invention in particular, to provide a wheel of minimumthickness and maximum diameter while stillmaintainingadequate stability against breakage, fracture, etc., resulting from the extremely high speed at which such wheels are operated and the forces developedthrough centrifugal force and resistance of the material being cut.. I'n the American Standard Safety Code relating to abrasive wheels, issued by American Standards Association, cutting wheels are deiined as having a thickness not. more than JAS of their diameter for wheels up to in diameter, and not more than 14,0 of the diameter of those larger than 20 in diameter.

It is an object of the present invention to provide an abrasive cutting wheel in which the body ofthe abrasive material extends outwardly from a point in close proximity tothe center of the wheel, and further to provide reinforcing plates or discsrenclosing a relatively large area of the central portion of the wheel, these plates ordiscs being inwardly offset from the side surfaces of a thickened'peripheral rim portion of the wheel. The central portion of the wheel is thus in the form of a sandwich, consisting of a relatively thinbody of the abrasiveV material'and the reinforcing plates at each side, and which is adapted for mounting between the anges ofadriving arbor.

It is further proposed to provide a. positive driving ,connection for: the central body ofthe abrasive wheelin the form of driving pins carried by the.. driving arbor.. and engaged in driving holes in the reinforcing plates and in the body of the wheel between them, to the endithat slippage between the wheel and the platesis overcome. and at. thefsame. timethe: body ofabrasive materaLbetWeen the plates is given added strengthto sustain any torsional or bending strains thereon.

A further object is to provide a cuttingwheel in-which the thin central area may be utilizedafter the thicker rim portion has been reduced; by wear'beyondtheoptimum; size for cutting large',diametermaterial, the thin central portion of the wheel previously betweenl thereinforcing plates being usable upon removal of the plates for conventional cutting operations.

Other objects and advantages of the invention will'become apparent from a consideration ofthe following detailed description taken in connection with the accompanying drawing wherein satisfactory embodiments of the invention are shown. However, itis to beunderstood that the invention is notlimited" to the detailsdisclosedv but includes all suchv variations" and= modifications 2,735,243 Patented. Feb. 211,. 1956 lCC 2. as fallwithin. thespiritof the invention'and thescope of the appended claims..

In the drawing.:

Fig. 1 isa front elevationalview showing a cutting wheel, accordingto the invention, in which the sideA surfaces of'the rim portion of the wheel are. segmented;

Fig. Z'is a top edge view;

Fig; 3'i's a verticalsectional view on an enlarged scale, taken along the line 3*-3 of Fig. 1;

Fig. 4 is'a verticalfsectional view similar to Fig. 3, and showing the cutting wheel attached to the anges of a driving spindle, also shown in vertical section;

Fig. 5 is a fragmentary sectional View taken along-the line 5 5 of Fig. l,v showing thelaminated structure making up the cutting wheel, and also showing one of the water. holes i therethrough;

Fig, 6`is a view similar to Fig. 5, showing a modified form ofthe water holes;

Fig, 7" is a sectionalview similar to Fig. 5, showing a modified form of. the invention in which the wheel is formed in one piece;

Fig. 8` is a front` elevational View showing` theV center portion of. the wheel following the removal through wear of the rim portion; and' Fig. 9 is a fragmentary front elevation of a modified form of thewlieel in.which the side surfaces of the rim portion are circumferentially continuous.

Referring to the drawings, and more particularly to Figs. 1-5 thereof, the improved abrasive cutting wheel, according to the illustrated exemplary embodiment of the invention', consists. ofa thin circular disc-shaped body member l'constituting the central body of the.wheel, and which is molded or. otherwise suitably formcd'of the usualJ abrasive materials, such as abrasive grain. and: a suitable bon'dsuch as resin,.rubb`er or the like, the material being subject during itsiformation to the usualcuring procedures.

Thismember 10 extendsV into close proximity to the center pointofthe wheel, being provided with a relatively small center'hole` 11 and then` provided in outwardly. space'drelation to the centerhole with a plurality of driving holes 12. While the diameter of the wheel may range from approximately 16" to 60, the'illustra'- tedwheel may beconsidered a typical example irr which thediameter of the bodymember 1b is 20", its thickness isV approximately Ms", and the diameter of the center hole"is"approximately 1". The rim portion of the wheel has an increased thickness over the center portion and comprisesthe body memberll) and laminations 13 and 14disposed at each side of the body member 10, these laminations*consisting'of3 sheets of abrasive material, of similar or of different material from the sheet' 10, of approximately 1A6 thickness in the illustrated example, and wh'charefbondedfto the body member 10 by` suitable bondingl material, the laminated structure being then suitably cured so thatfthe structure of the laminated rim portion is, iii-effect, a homogeneous mass of'abrasive material.

Thelarninatlon layerslfal and 14 are in the formiof segmentsioffa'ringzwith Vthe adjacent edges ofthe vsegments radially. disposedand spaced from eachother so asnt'o produceiazradially extendinggroove' 15 between thefadjacent segments, this'v4 groove in the illustrated example being approximately- 1A," in. width;` The grooves 15. at one sideare-preferably instaggered relation -to the grooves at theother side. Thelradialdimension of the rim portion is approximately,r equal to the radial dimension of the. center portion, although this relationship may be varied within limits, as desired, to produce the proper rigidity at'thecuttingperiphery. The grooves 15', in addition to` formingwater grooves for feeding water to the periphery of the wheel, alsoprovide aY series ofclearance breaks in the periphery of the wheel, which provides a better cutting action, in that they prevent portions of the removed metal of the material being cut from collecting upon the periphery of the wheel and causing glazing.

The wheel is further provided with water holes 16 which are arranged in a pattern designed to produce a proportional reduction in weight toward the periphery and therefore reduce the effect of centrifugal force upon the rim section of the wheel. The arrangement preferably consists in disposing a plurality of series of spaced holes along circumferentially spaced spiral lines extending from the periphery of the wheel to a point near the center. Additional holes may be provided near the periphery to further reduce the mass. While the holes are shown as extending through the wheel, they may, as shown in Fig. 6, be provided only in the laminations 13 and 14, in which case they form pockets 16a.

As seen in Fig. 3, the abrasive cutting wheel has a relatively large diameter center portion extending from the inner periphery of the rim portion into close proxirnity to the center of the wheel, and at each side of this center portion is recessed with respect to the side surfaces of the rim portion. In mounting the wheel, circular reinforcing plates or discs 17 and 1S, of metal or other suitable rigid material, are placed in these recesses at each side of the central abrasive body portion 10 of the wheel, the plates having an outer diameter slightly less than the diameter of the inner periphery of the rim, so that they fit freely therein, and having a thickness slightly less than the thickness of the laminations 13 and 14 of the rim portion of the wheel, so that their outer surfaces are inwardly offset from the outer side surfaces of the rim portion of the wheel. This allows the cut being made by the Wheel to extend beyond the inner periphery of the rim portion of the plates 17 and 18 to a point where the mounting hub will prevent further depth of cut. The plates 17 and 18 are each provided with a center hole 19 and driving holes 2t] in register withthe center hole 11 and driving holes 12 of the abrasive wheel.

The driving spindle Z1 has a hub flange 22 secured thereon which carries a center stud 23 engaged through the center holes 11 and 19 of the abrasive wheel and reinforcing plates, the flange also having a series of driving studs 24 engaged through the driving holes 12 and 20 of the abrasive wheel and plates. A flange plate 25 having a center hole 26 and driving stud receiving holes 27 is engaged at the opposed side of the wheel from the flange 22, and is clamped to secure the wheel by a lock ring 28 screwed upon a threaded extension 29 of the hub 23 and bearing upon the forward face of the flange plate 25.

In Fig. 7 there is shown a modied form of the invention in which the rim portion 10a of the wheel is formed as a one-piece structure with respect to the center portion 10b, as distinguished from the laminated structure shown in Fig. 5, this structure being produced by molding or pressing and suitable curing of the bonded abrasive material. In this case, the grooves 15, as shown in' Fig. l, will be molded or cut in the sides of the rim portion.

In Fig. 9 there is shown a modified form of the invention in which the side surfaces 30 of the rim portion of the wheel are circumferentially continuous, there being no radial grooves i5. Obviously, this wheel may be formed by either of the methods shown in Figs. 5 and 7, i. e., by a laminated structure or a one-piece structure.

Fig. 8 illustrates the center portion of the wheel following the wearing down of the rim portion, this center 'portion then being usable as a conventional cutting wheel upon removal of the metal plates 17 and 18. It may be mounted between the flanges of a driving spindle similar to that shown in Fig. 4, in which case suitable blotters or metal plates may be disposed at each side for protection, these being of substantially the diameter of the .flanges of the driving spindle.

What is claimed is:

l. An abrasive wheel of the cutting wheel type having a thickness not more than 1/48 of the diameter for Wheels up to 20 diameter and not more than 1/60 of the diameter for wheels larger than 2D" diameter, comprising a circular disc including a circular material cutting rim portion of bonded abrasive material having Hat substantially parallel side surfaces and a material cutting central portion of bonded abrasive material integral with said rim portion having its side surfaces inwardly offset with respect to the side surfaces of said rim portion, said cutting wheel presenting a continuous cutting periphery throughout the life of the rim portion and the central portion thereof, the thickness between the side surfaces of said rim portion determining the width of cut during the cutting life of said rim portion and the thickness between the side surfaces of said central portion determining the width of cut following the wearing away of the rim portion.

2. The invention as defined in claim l, further characterized in that said rim portion has at'each side a series of radially extending grooves terminating at the outer periphery of said central portion.

3. The invention as defined in claim l, further characterized in that said rim portion has at each side a series of radially extending grooves terminating at the outer periphery of said central portion, the bases of said grooves being substantially ilush with the side surfaces of said central portion.

4. The invention as defined in claim l, further characterized in that said rim portion has at each side a series of radially extending grooves terminating at the outer periphery of said central portion, the grooves at one side being in staggered relation to the grooves of the other side.

5. The invention as defined in claim l, further characterized in that said wheel comprises a medially disposed circular sheet of material including a central portion forming the central portion of the wheel and a rim portion forming a medial lamination of the rim portion of the wheel, and said rim portion of the wheel further includes lamination sheets of material bonded to the sides of said rim portion of said circular sheet of material.

'6. The invention as defined in claim l, further characterized in that said wheel comprises a medially disposed circular sheet of material including a central portion forming the central portion of the wheel and a rim portion forming a medial lamination of the rim Vportion of the wheel, said rim portion of the wheel further includes lamination sheets of material bonded to the sides of said rim portion of said circular sheet of material, said lamination sheets of material at each side consisting of a plurality of segments of a circular ring having the adjacent edges of said segments radially disposed and spaced apart to provide radial grooves.

7. The invention as defined in claim l, further characterized in that said wheel comprises a medially disposed circular sheet of material including a central portion forming the central portion of the wheel and a rim portion forming a medial lamination of the rim portion of the wheel, said rim portion of the wheel further includes lamination sheets of material bonded to the sides of said rim portion of said circular sheet of material, said lamination sheets of material at each side consisting of a plurality of segments of a circular ring having the adjacent edges of said segments radially disposed andspaced apart to provide radial grooves, the grooves at one side being in staggered relation to the grooves at the other side.

8. In combination, an abrasive wheel of the cutting wheel type having a thickness not more than 1/48 of the diameter for wheels up to 20" diameter and not more than lo of the diameter for wheels larger than 20 diameter, comprising a circular disc including a circular material cutting rim portion of bonded abrasive material having tlat substantially parallel side surfaces and a material cutting central portion of bonded abrasive material integral with said rirn portion having its side surfaces inwardly oset with respect to the side surfaces of said rim portion, said cutting wheel presenting a continu ous cutting periphery throughout the life of the rim portion and the central portion thereof, the thickness between said side surfaces of said rim portion determining the width of cut during the cutting life of said rim portion and the thickness between said side surfaces of said central portion determining the width of cut following the wearing away of said rirn portion, and a pair of discs respectively tted in the recesses at each side of the central portion of said abrasive wheel and freely removable from the side surfaces of said central portion, the outer surfaces of said discs being inwardly ofset from the side surfaces of said rim portion.

References Cited in the file of this patent UNITED STATES PATENTS King Feb. 8, Robinson Feb. 20, Webster Jan. 7, Sohlstrom Sept. 7, Kuzmick Jan. 6, Pare Oct. 31, Allison Dec. 28, Martin Oct. 23, Belcher Mar. 18, Hough Nov. 4,

FOREIGN PATENTS Great Britain Sept. 9, France May 26, France Sept. 28,

France Oct. 10, 

